When the grover's algorithm is applied to search an unordered database, the probability of getting correct results usually decreases with the increase of marked items. The reason for this phenomenon is analyzed in...
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ISBN:
(纸本)9781479900305
When the grover's algorithm is applied to search an unordered database, the probability of getting correct results usually decreases with the increase of marked items. The reason for this phenomenon is analyzed in this Letter, the grover iteration is studied, and a new phase matching is proposed. With application of the new phase matching, when the fraction of marked items is greater than 1/3, the probability of getting correct results is greater than 25/27 with only one grover iteration. The validity of the new phase matching is verified by a search example.
Some cryptographic applications of quantum algorithm on many qubits system are presented. We analyze a basic concept of grover algorithm and it's implementation in the case of four qubits system. We show specially...
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ISBN:
(纸本)9781467326797
Some cryptographic applications of quantum algorithm on many qubits system are presented. We analyze a basic concept of grover algorithm and it's implementation in the case of four qubits system. We show specially that grover algorithm allows as obtaining a maximal probability to get the result. Some features of quantum cryptography and Quantum Secret-Sharing protocol based on grover's algorithm are also presented.
In recent years there has been an increasing focus on the pattern recognition, especially multi-pattern recognition in computer science. This paper investigates the issue in a new way built upon the quantum computatio...
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In recent years there has been an increasing focus on the pattern recognition, especially multi-pattern recognition in computer science. This paper investigates the issue in a new way built upon the quantum computation theory and presents a multi-pattern recognition method based on grover's algorithm. This method not only introduces a new design scheme of initializing quantum state and quantum encoding on the pattern set, but also details the process of quantum multi-pattern recognition using several unitary operators. Owing to the power of quantum parallelism, this new method can recognize multi-pattern simultaneously with a certain probability in the given pattern set. Mathematic calculations and simulation result in recognizing "XOR" and three-class hybrid pattern show that the proposed method can accomplish multi-pattern recognition with the probability of almost 80%, which displays one tempting foreground for quantum multi-pattern recognition.
The current grover quantum searching algorithm cannot identify the difference in importance of the search targets when it is applied to an unsorted quantum database, and the probability for each search target is equal...
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The current grover quantum searching algorithm cannot identify the difference in importance of the search targets when it is applied to an unsorted quantum database, and the probability for each search target is equal. To solve this problem, a grover searching algorithm based on weighted targets is proposed. First, each target is endowed a weight coefficient according to its importance. Applying these different weight coefficients, the targets are represented as quantum superposition states. Second, the novel grover searching algorithm based on the quantum superposition of the weighted targets is constructed. Using this algorithm, the probability of getting each target can be approximated to the corresponding weight coefficient, which shows the flexibility of this algorithm. Finally, the validity of the algorithm is proved by a simple searching example.
The quadratic reduction of query complexity of grover's search algorithm (GA), while significant, would not be enough to enjoy exponentially fast data searching in large-scale quantum computation. One of the ways ...
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The quadratic reduction of query complexity of grover's search algorithm (GA), while significant, would not be enough to enjoy exponentially fast data searching in large-scale quantum computation. One of the ways to enhance the speedup in the framework of grover's algorithm is to employ a novel quantum operation, i.e., inversion against an unknown state;however, this is not possible at least in quantum theory. We thus extend the grover algorithm assisted by closed timelike curves (CTCs), in which the unknown-state inversion is achievable by combining the superposition of two unknown states with cloning. We dubbed this refined algorithm CTC-assisted grover algorithm (CTC-GA). We show that the CTC-GA can vastly reduce the query complexity compared to the original algorithm;remarkably, from polynomial to poly-logarithmic. These results will provide a broader intuition for exponential quantum speedup of data searching problems.
grover algorithm is a quantum search algorithm that can find the target state efficiently. However, with the increase in the amount of searching data, the circuit of grover algorithm is faced with complex gate decompo...
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grover algorithm is a quantum search algorithm that can find the target state efficiently. However, with the increase in the amount of searching data, the circuit of grover algorithm is faced with complex gate decomposition problem. In today's NISQ era, resources are very limited, so the depth of circuit is an important metric. This paper introduces a two-stage quantum search algorithm based on divide-and-conquer, which can run quickly in parallel on a quantum computer. A circuit optimization method is proposed to reduce the number of iterations by using block-level oracle circuit. Combining this method with divide-and-conquer idea, it is defined as the 2P-grover algorithm. The simulation experiment was carried out on the quantum computing framework Cirq and compared with grover algorithm. The experimental results show that the 2P-grover algorithm can reduce the depth of circuit by at least 1.2 times and maintain a high probability of search success.
In the original grover algorithm, an exact or almost exact search such that the success probability is unity or infinitesimally close to unity is possible only for certain values of the fraction lambda = M/N where M i...
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In the original grover algorithm, an exact or almost exact search such that the success probability is unity or infinitesimally close to unity is possible only for certain values of the fraction lambda = M/N where M is the number of marked items that are stored in an unsorted database of N items. There are various modified algorithms with an adjustable phase or phases such that an exact search can be done for any value of lambda by means of a finite number of grover-type operations. Among them, the algorithm proposed by Long is the simplest in the sense that it has only one adjustable phase and that the phase can be obtained in a closed form. We show that other more general algorithms with additional phases are not more efficient than Long's version with a single phase.
With the rapid development of quantum computing technology, the traditional cryptosystem will face a significant threat. It is an urgent security issue to study the security impact of quantum computing on classical cr...
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With the rapid development of quantum computing technology, the traditional cryptosystem will face a significant threat. It is an urgent security issue to study the security impact of quantum computing on classical cryptosystems and provide reliable cryptographic primitives for the post-quantum era. A powerful way to solve this problem is to quantize the classical cryptanalysis tools and use the improved versions for cryptanalysis. In this paper, we propose a quantum Zero-correlation analysis algorithm based on the Bernstein-Vazirani and grover algorithms. It can find zero-correlation linear hulls for Feistel and SPN structures. We prove the correctness of the algorithm and analyze its complexity. Compared with the classical algorithms, the proposed quantum algorithm has significant advantages when the number of encryption rounds of block ciphers is large. Moreover, compared with the existing quantum Zero-correlation linear analysis, the proposed algorithm is more efficient and does not depend on the algebraic characteristics of the target cipher, which makes the algorithm has more flexible application scenarios. With the development of quantum computers, we discuss the threat of quantum cryptanalysis algorithms to classical security.
The grover algorithm and its underlying amplitude amplification process are one of the most essential and widely used building blocks of many other subsequent quantum methods. In this work, we adapt grover's searc...
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ISBN:
(纸本)9781665494939
The grover algorithm and its underlying amplitude amplification process are one of the most essential and widely used building blocks of many other subsequent quantum methods. In this work, we adapt grover's search algorithm to find pure Nash equilibria in graphical games. In general, the main complexity lies in the construction of the algorithm's oracle operator. We show how to set up the oracle from a given graphical game by translating it to a Boolean satisfiability problem, which can subsequently be logically synthesized to an oracle quantum circuit. We investigate the algorithm for random graphical game instances on IBM's quantum simulator and give an outlook regarding the scaling of it.
The system proposed in this paper will be used to implement the Groove quantum computation search algorithm: look in a content addressable memory and find location for a data. Unlike other solutions implemented in FPG...
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ISBN:
(纸本)9781728116242
The system proposed in this paper will be used to implement the Groove quantum computation search algorithm: look in a content addressable memory and find location for a data. Unlike other solutions implemented in FPGA, our solution is trying to achieve the performance of a quantum computing system on resources allocated and search speed.
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